Vehicular panel assembly and method for making same

ABSTRACT

A panel assembly and method for manufacturing the panel assembly, especially adapted for use in vehicles, includes a panel of predetermined size and geometry wherein a surface of the panel to receive a gasket is primed using a material especially adapted to prepare the panel surface to bond with the gasket. The desired gasket profile is molded separately from the panel from a polymeric material. Following formation of the gasket, the panel is located thereon and pressed into intimate contact with the gasket for a prescribed period of time. The panel and attached panel are removed as an assembly. Additional or optional steps may be followed including preheating the panel and primed surface prior to bonding to shorten the cycle time and improve adhesion. Moreover, heat may be applied to the contact boundary between the panel and gasket substantially simultaneously with the application of pressure. The steps of heating and applying pressure may be repeated to insure proper adhesion. The panel assembly and the method of manufacturing the panel assembly are especially adapted for use in flush mounted panel assemblies wherein the gasket is fixed only to a single surface of the pane and allows for gradationally varying cross-sectional profiles to specifically suit a needed application.

This is a division of application Ser. No. 08/898,094, filed Jun. 12,1992, now U.S. Pat. No. 5,443,673.

BACKGROUND OF THE INVENTION

This invention relates to panel assemblies especially adapted for use aswindows in vehicles buildings or other structures, as well as a methodfor manufacturing such panel assemblies.

Relatively recent in the history of vehicle panel assemblies, gasketshave been molded or extruded directly onto the window panel. In moldedwindow panels, a sheet of glass is closed within a molding tool and apolymeric material is then injected around the opposing surfaces of theperipheral edge thereby capturing the peripheral edge of the glass panelwithin the injected polymeric gasket. After the gasket is cured, themold is opened and the panel assembly is removed. To retain the moldedpanel assembly within the vehicle, studs or clips may be molded withinor attached to the gasket and used to engage the pinch weld flangeforming the vehicle opening. Alternately, or in addition, a bead ofadhesive is also often applied to bond the glass panel directly to themetal pinch flange. A bezel may be molded with the gasket to decorateand/or conceal space between the vehicle and the window assembly.

New styling requirements are calling for flush-mounted glass panelshaving an exposed edge. One flush-mounted vehicle panel assembly on themarket includes extruded gaskets deposited directly on one surface of aglass sheet. Often the extrusion includes two adhesive beads ofpolyurethene compounds, one deposited by the panel assembly manufacturerand the other applied by the vehicle assembler. Disadvantages associatedwith extruded gaskets include long cure time for the first bead, addingcycle time to manufacturing, and constant cross-sectional profiles. Inaddition to being limited to uniform cross-sectional profiles, thegasket material used in forming extruded gaskets is typically not UVstable by itself and can degrade over time. Moreover, the extrusion doesnot easily adapt itself to receive mounting studs or clips. Theextrusion compound is expensive and requires special storage andhandling once formed and cannot be fully completed without creating aseam or gap in the gasket layout.

Another window assembly intended for use in flush-mounted applicationshad a gasket molded directly to a single surface in a molding machineusing reaction injection molded (RIM) urethane. Although this techniqueoffered some variable cross sections, the presence of the glass andtooling limitations prevented or precluded gaskets having undercuts orlips. Other disadvantages include instability when subjected toprolonged exposures of ultraviolet light, long cycle times in forming,and increased material costs compared with other materials such as PVC.In addition, tensile or shear forces applied between the glass andgasket result in failure of the adhesive seal of the gasket with thepanel as opposed to the desired loss of cohesion in the gasket itself.

None of the prior panel assemblies or methods are as versatile inproviding flush mounted panel gaskets having unique cross-sectionalprofiles, with or without attaching or otherwise capturing fasteners.Moreover, none of the prior methods or panel assemblies can provideflush-mounted panel gaskets having cross-sectional profiles which arevariable along the panel assembly and satisfy complex sealingrequirements.

SUMMARY OF THE INVENTION

Accordingly, the present invention includes a unique panel assembly,especially for vehicles having a gasket formed on a single surface foruse in flush-mounted panels, and a method for making the panel assembly.Moreover, this invention provides new and unique gasket cross sectionshaving special applications in both fixed and movable panel assemblieswhich could not previously be obtained using conventional moldingprocesses.

The method for manufacturing the panel assembly, especially adapted foruse in vehicle windows, includes the steps of priming a surface of thepanel adapted to receive the gasket using a material especially adaptedto prepare the glass surface to bond with the gasket. The desired gasketprofile is formed from a polymeric material in a mold separately fromthe glass panel. Once the gasket is formed, the glass panel isappropriately located with respect to the gasket while in the mold andpressed into contact with the bonding surface of the gasket to promoteadhesion. The glass panel and attached gasket are then forwarded on as afinished product.

In a preferred form of the method, the panel is preheated afterreceiving the primer to drive off any carriers/solvents and elevate theenergy level of the bonding agents present in the primer. Substantiallysimultaneously with the step of pressing the preheated panel intocontact with the gasket, additional heat energy is applied to thecontact boundary between the panel and gasket in order to further thebonding process. The heat energy may be applied using any one of anumber of sources, although focused infrared radiation is preferred.

As an alternate form of the invention, or in addition to the stepsoutlined above, once the gasket is bonded to the panel to form the panelassembly, it may be subjected to a final compressive force and/orradiation treatment. The assembly may be located in a separate fixturewhere the panel is again forced against the contact surface of thegasket. Radiant or other energy is focused to heat the contact boundary.The primer, activated by the application of heat and pressure up to aslong as 30 seconds, is energized to a state to chemically bond with thegasket.

In another form of the invention, preheating of the panel may be reducedor eliminated by applying the primer to the gasket surface after beingformed. Moreover, if preheating is desired, heat may be applied to thepanel from one or both sides.

The method of this invention is preferred in the manufacture of a panelassembly especially adapted for use in vehicles. More particularly, themethod is used to manufacture window panel assemblies for vehicleswherein the glass panel is held within the vehicle by one or moregaskets bonded to a single surface of the panel.

The panel assembly manufactured by the above process includes asheet-like panel having at least one surface area coated with a heatactivated primer. A gasket having a body supported by at least onesecuring surface is formed separately from the sheet-like panel. Thesecuring surface(s) of the gasket are urged into contact with the primedsurface of the panel while still retaining a portion of heat generatedduring the formation process. The remnant heat in the gasket activatesthe primer to bond with the gasket. The resulting product or panelassembly is a sheet-like panel having a gasket securely attached to atleast a portion of at least one surface.

In an alternate embodiment of the panel assembly, the preformed gasketmay have a variety of cross-sectional profiles and each of these maychange in size along the gasket to meet very specific applications. Anarciform gasket may be made according to the method and have one or moresecuring surfaces or flanges in contact with the panel. The arciform,curved body may include a gas-filled cavity wherein one wall of thecavity is formed by the panel. The cavity may be sealed or perforated toprovide an appropriate seal for the application.

In another embodiment of the panel assembly, the gasket may have a lipor flap which extends beyond the peripheral edge of the panel to form aflexible, resilient seal with the vehicle body.

In yet another embodiment of the panel assembly, one securing flange orsurface of the gasket may be enlarged, adapted to capture a mountingstud or locating device inserted in the gasket forming process andadapted to locate or retain the panel assembly in the vehicle.

As will be understood from the invention, numerous advantages for panelassemblies and the methods of making the same are provided by thisinvention. These include manufacturing simplification by eliminating theneed for complex molding tools machined to a fine tolerance to acceptcurved, sheet-like glass or other panels. The inventive method providesa significantly better manufacturing consistency and tolerance forfitting the gaskets to the sheet-like panels over prior known singlesided, extruded or other techniques. Moreover, the method provides panelassemblies having a continuous gasket wherein the cross-sectionalprofile and/or size of the profile may vary continuously along thelength of the gasket. Alternately, separate gaskets, each of a differentshape or size may be applied to separate surfaces of the panel, or toseparate areas of the same panel surface. This unique ability to changethe shape of the gasket for a given portion of the window provides theoptimum amount of gasket to seal the window in the opening wherein theprior constant profile gaskets provided either too much or not enoughgasket to seal the opening. Furthermore, this method allows strong,secure attachment of the gasket to a single side of the sheet-like panelso that the exterior surface of the panel assembly is substantiallyflush with the exterior sheet metal portion of the vehicle body.

The panel assemblies manufactured according to the above method haveadvantages in that the gasket on the panel may be specifically formed toprovide a specific function which changes around the perimeter of thewindow panel. The panel assembly requires less material than prior knownfully encapsulated panel assemblies, thus resulting in a less costlyproduct. Moreover, because of the lower pressures required to bond thegasket to the sheet-like panel, fewer panels are broken during themanufacturing process. Yet another advantage of the instant invention isthe ability to place the panel assembly in existing vehicles with variedand/or more complex gasket designs for sealing the panel assembly in thevehicle.

Further benefits and advantages of the invention are the ability to formgaskets for panels that could not be made using traditional molding orextruding techniques. These include unusual cross sections such as bulbseals and lip seals having the ability to contain various attachmentdevices, while providing a flush mounting arrangement of the panelexterior. The method and panel assemblies of this invention haveparticular applications in Class "A" window panels for use in vehiclewindshields, gaskets on laminated panels, and panel assemblies formovable windows.

These and other objects, advantages, purposes and features of theinvention will become more apparent from a study of the followingdescription taken in conjunction with the drawing figures describedbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary view of a panel assembly of the inventionmounted in a vehicle opening;

FIG. 2 is a fragmentary sectional view of the panel assembly taken alonglines II--II;

FIGS. 3a-3d schematically illustrate one embodiment of the method ofthis invention;

FIGS. 4a-4j schematically illustrate a preferred embodiment of themethod and panel assembly of this invention;

FIGS. 5a-5k schematically illustrate an alternate embodiment of themethod and panel assembly of this invention;

FIGS. 6a-6e schematically illustrate yet another embodiment of themethod;

FIG. 7 is a fragmentary section view of yet another embodiment of apanel assembly that may be used in FIG. 1;

FIG. 8 is a fragmentary section of another embodiment of a panelassembly that may be used in FIG. 1;

FIG. 9 is a fragmentary section view of yet another embodiment of apanel assembly for use in movable panels;

FIG. 10 is a fragmentary section view of still another embodiment of apanel assembly made in accordance with the method;

FIG. 11 is a fragmentary section view of one embodiment of a class "A"panel assembly made in accordance with the inventive method;

FIGS. 12 and 13 illustrate two examples of energy sources used in themethod; and

FIGS. 14-15 generally illustrate alternate pressure applicationtechniques between the gasket and sheet-like panel used in the method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, like reference numerals may be used ineach of the figures to indicate like components, wherein FIGS. 1 and 2illustrate one embodiment 20 of the window panel assembly of the presentinvention. Assembly 20 is specifically adapted for use as a vehiclewindow and includes a panel or sheet 22 of transparent glass which maybe tempered, laminated or otherwise strengthened with conventionaltechniques/principles. Sheet 22 has two substantially parallel sides orfaces 24, 26 which terminate at a peripheral edge 28. Althoughtransparent glass is preferred, other panel materials such as opaque orcoated glass, or transparent, coated or opaque plastic materials, ormulti-composite laminates such as transparent glass and plastic couldalso be used. Sheet 22 may also include an opaque, and preferably blackceramic frit layer or coating 30 applied and adhered to one surface suchas 26 covering and concealing an area adjacent peripheral edge 28.

Fixed to surface 26 and/or ceramic frit layer 30, and extending alongand around at least a portion of sheet 22 proximate peripheral edge 28,is a flexible, resilient gasket or grommet 32 intended to provide aweather seal with a portion of a vehicle body when assembly 20 isinstalled. In FIG. 1, gasket 32 is shown to extend around the entireperimeter of surface 26.

In FIG. 2, gasket 32 includes a body 34 having a generally rectangularcross section defining a first surface 36 disposed toward sheet 22.Although surface 36 may be substantially smooth, it may contain anirregular or patterned texture to provide a greater surface area to bondto frit layer 30. An opposite surface 38 is shown to include arectangular channel 40 extending along the length thereof. Channel 40,in turn, defines first and second flanges 42, 44 on either side thereofand which run adjacent channel 40. Running the length of gasket 32 andextending laterally from flange 44 is a resilient, flexible lip seal 46.Seal 46 is generally arcuate, having a radius located toward sheet 22,and terminating beyond peripheral edge 28. Gasket 32 is shown withsurface 36 engaging and bonded by primer adhesive 48 to frit layer 30deposited on sheet surface 26.

The size and/or thickness of body 34 and seal 46 may vary depending uponthe gap to be closed, and the sealing force necessary in the vehicleafter installation along a given length of the gasket. For example,gasket portion 32A (FIG. 1) may have a high profile while gasket portion32B at the opposite side of panel 22 may have a low profile. Gasketportions 32C and 32D may have gradational profiles decreasing in sizefrom portion 32A to portion 32B. As will also become more apparentbelow, a panel such as panel 22 may have a gasket with more than onecross-sectional profile, or may have separate gasket portions of thesame or differing size, thickness and/or profile.

Although gasket or grommet 32 may be made using a variety of techniques,including liquid or slurry molds, and compression molding, the preferredtechnique is injection molding using a polymeric thermoplastic materialsuch as polyvinyl chloride (PVC). However, other molding materials canalso be used with the above methods including reaction injection molded(RIM) urethane and thermoplastic elastomers such as thermoplastic rubber(TPR), thermoplastic urethane (TPU) and thermoplastic olefin (TPO).

FIGS. 3A-3D schematically illustrate one embodiment of the inventivemethod. Sheet 22 may be conveyed to a preparation area where one surfacesuch as peripheral area 26 near edge 28 may be cleaned with a solventsuch as methylethylketone to remove oils, dirt or other debris which mayinterfere with the bonding process. A coating 48 of primer material isapplied to surface 26 and/or frit layer 30 to prepare the panel surfaceto receive gasket 32. The primer is selected to enhance the adhesionbond between gasket 32 and sheet surface 26 and/or frit layer 30 and maybe any of several varieties depending on the material of gasket 32 andsheet 22 such as heat and/or pressure activated compositions. The primermay be applied by brush, pad, roller or spray and be allowed to whollyor partially dry to obtain a substantially uniform, even and aeriallyrestricted primer coating. A preferred primer for PVC gaskets is soldunder the designation A-1100-B combined with an adhesion promoterdesignated A-1167-B and produced by B. F. Goodrich Co. of Akron, Ohio.

Substantially simultaneously with the preparation of sheet 22, gasket 32is formed, preferably using conventional injection molding techniques.As shown schematically in FIG. 3b, one such tool 50 includes an uppermold half 62 having a channel 58. Tool 50 also includes a lower moldhalf 52 having channels 54, 56 for forming flanges 42, 44 and the outerradius of lip seal 46. Channel 58 and ridge 60, formed in upper moldhalf 62, and channels 54, 56 in lower mold half 52 combine to form amold cavity 64 in which body 34 and lip seal 46 of gasket 32 are definedand molded. Preferably, molding is carried out with polyvinyl chloride(PVC) such as 48562 available from Vista Chemical Co. of Aberdine, Miss.If a mold release agent is used, the agent should be cleaned from thegasket before adhering it to the panel. If not cleaned, the mold releaseagent may inhibit the bonding of the gasket to any other material suchas panel 22.

Following the forming of gasket 32, one-half of tool 50, such as 62, isremoved leaving gasket 32 within mold half 52. Because gasket 32 isformed by cooperating tool halves 52 and 62, surface 36 has a positiverelief with respect to surface 66 of tool half 52 when opened. Gasket 32may be retained within mold half 52 using a variety of techniques,including mold undercuts, protrusions, core pins and the like, none ofwhich are shown.

With gasket 32 held by mold half 52, molding tool 50 may be opened.Sheet 22 is removed from preparation area and precisely located ongasket 32 with locating pins, templates, guides or the like to placeprimed surface 48 into contact with surface 36 (FIG. 3C). Because gasket32 is still hot from the molding process (between 100° and 300° F.),gasket 32 activates primer 48 to bond gasket 32 with surface 26 and/orfrit layer 30. The bond is improved by pressing sheet 22 against surface36, insuring an optimum surface area is in uniform, complete contactwith the primed surface 48. After a predetermined period of time(between 3 and 20 seconds) allowing gasket 32 to bond with and cure onsheet 22, the panel 22 and attached gasket 32 are removed from lowertool half 52 as panel assembly 20 (FIG. 3d) and moved on as a finishedproduct where it is packaged for shipping.

The above process, using the remnant heat of the injection moldingprocess, together with the compression of sheet 22 against surface 36,may be sufficient to form a strong, bond adhering gasket 32 to sheet 22.A variety of devices may be used in locating sheet 22 on gasket 32including the use of locating pins, and/or guided robotic arms (notshown) having the ability to precisely locate each panel.

Although the above procedure described in reference to FIGS. 3A-3D bondsgasket 32 to surface 26 and/or frit layer 30 of sheet 22, it ispreferred that certain additional and/or optional steps be performed tofurther improve the strength of the bond between gasket 32 and sheet 22.Referring to FIGS. 4A-4J, a preferred method for making panel assembly20 includes obtaining a sheet or panel 22, preferably of glass and ofpredetermined geometry, to receive gasket 32. Panel 22 may include aceramic frit coating 30 (FIG. 2) deposited on at least one surface suchas 26 proximate peripheral edge 28. Once the appropriate sheet 22 isselected, the perimeter of surface 26 and frit layer 30 adapted toreceive gasket 32 may be cleaned using any one of a variety ofprocedures to provide a clean bonding surface. As briefly mentionedabove, a solvent such as methylethylketone may be applied to surface 26and frit layer 30 to remove any oil or other debris which might inhibitbonding. A primer coating 48 is applied to that portion of sheet 22 andfrit layer 30 to receive the gasket. For certain types of sheets 22without a cosmetic frit coating, primer coating 48 may be applieddirectly to t e sheet. Primer coating 48 may be applied to sheet 22 in aspray, by a pad, brush or roller. With sheet 22 prepared, it ispreheated to drive off any remaining carriers/solvents and raise thetemperature of primer coating 48 and frit layer 30 to between 150° and350° F. (FIG. 4C). The energy necessary to heat frit layer 30 and primer48 may be generated by a number of sources and directed into the fritlayer in a variety of directions, the details of which are explainedmore fully below.

Gasket 32 is formed substantially simultaneously with the preheating ofsheet 22. Tool cavity 64 (FIG. 4D) formed by tool halves 52, 62 isinjected with a polymeric material such as PVC (FIG. 4E) as describedabove. After a predetermined period of time sufficient for gasket 32within tool 50 to substantially cure, set up or harden, halves 52, 62are separated so that surface 36 extends above upper surface 66 of lowertool half 52 (FIG. 4F).

After tool 50 is opened, exposing surface 36 of gasket 32, and beforegasket 32 substantially cools down, heated sheet 22 is precisely locatedon gasket 32 still retained by tool half 52 using locating pins,templates, guides or the like. Surface 26 and primer coating 48 areurged against surface 36 for a predetermined period of time between 3and 30 seconds. The force used to urge sheet 22 against surface 36 ofgasket 32 should be sufficient to assure that substantially all ofsurface 36 is in uniform contact with primed surface 48 and bondedtherewith. The amount of pressure required to optimize the contactbetween sheet 22 and surface 36 is dependent upon several factors,including the total surface area of surface 36 in contact with sheet 22,the size and geometric shape of sheet 22, the temperature of gasket 32and sheet 22, and the exact nature of the material forming gasket 32.For example, for a substantially flat glass sheet 4 millimeters thick,having a surface area of approximately 1 square meter, and a 85Durometer (Shore A) PVC gasket extending substantially around theperimeter of the sheet with a one inch wide bonding surface 36, thepressure required to affect a secure bond is between one-half and fiveatmospheres or approximately 7 to 75 pounds per square inch (psi).

Substantially simultaneously with the forcing of sheet 22 againstsurface 36 of gasket 32, a radiant or electromagnetic energy is appliedfor approximately 3 to 30 seconds to frit coating 30 between surface 36,primer coating 48 and surface 26 of sheet 22. Preferably, infraredenergy is focused using a CFIR heat source, described below, to have themaximum effect on frit layer 30. Depending upon the materials used toform gasket 32, and the temperature of sheet 22 and gasket 32, the timerequired to maintain sheet 2 against surface 36 (FIGS. 4H, 4I) willvary. For PVC and A-1100-B primer mixture described above, it iscontemplated that a pressure of approximately 14 psi and heat raisingthe temperature to approximately 300° F. may be applied approximatelybetween 3 and 30 seconds. Following the application of pressure and heatfor the predetermined period of time, the bond between gasket 32 andsheet 22 should be optimum. At this point, panel assembly 20, includingsheet 22 and bonded gasket 32, may be removed from lower tool 52 (FIG.4J) and moved on as finished goods.

In an alternate embodiment of the invention (FIGS. 5A-5K), two gasketsadapted to be adhered to opposite portions of panel 22 are formedsimultaneously. Tool 50a is adapted to receive an insert 70 having arecess or channel 72 on one surface 74 adapted to fit in registeredalignment with groove or channel 76 in tool half 52a combining to form atool cavity 78 (FIG. 5D) to form one gasket 32. An opposite surface 80of insert 70 contains a channel 82 which fits in registered alignmentwith a contoured channel 84 defined in tool half 62a to form cavity 86(FIG. 5E) to form a seal or second gasket 88. Again, a mold releasematerial may be applied to the surfaces of insert 70, as well aschannels 76, 84 to prevent the formed gaskets 32, 88 from sticking. Thismay be particularly true to the surfaces of the insert forming portionsof the mold cavities. With tool halves 52a and 62a closed about insert70, polymeric material, such as PVC, is injected into each cavity 78, 86to form first gasket 32 and second gasket or trim piece 88 (FIG. 5F).

With gasket 32 and trim piece 88 substantially cured or hardened, butstill retaining heat produced during the molding process, tool 50a isopened retaining trim piece 88 in tool half 62a, and gasket 32 retainedin tool half 52a (FIGS. 5G-5H). If a mold release agent is used,mechanical means may be used to retain the gaskets in their respectivemold halves 52a, 62a such as pins, undercuts in the channels, or by avacuum. Without the mold release agent, each gasket should stay in thechannel in each mold half 52a, 62a without the above structures. Witheach gasket and/or seal held by tool halves 52a, 62a, insert 70 isremoved (FIG. 5H) and heated sheet 22 is precisely located by pins orother mechanisms on gasket 32 contained in tool half 52a (FIG. 5I). Asin the previous embodiment, sheet 22 is located so that primed surface26 engages surface 36 of the gasket. With sheet 22 properly located ongasket 32, tool half 62a, retaining trim piece 88, is closed placingsurface 90 of trim piece 88 into intimate contact with surface 24 (FIG.5J). Preferably, surface 24 which will contact surface 90 of trim piece88 has been previously primed in the same manner as surface 26. Trimpiece 88 is positioned on sheet 22 by tool half 62a such that aresilient, flexible lip 89 extends beyond the peripheral edge of sheet22 to form a weather or lip seal. It is preferred that surfaces 36, 90of gasket 32 and trim piece 88, respectively, be urged into intimatecontact with surfaces 24, 26 of sheet 22 by closing tool 50a to assurecompletion of the bond over the maximum possible surface area. At thistime, heat may be applied to raise the temperature of the bondingsurface or contact between each polymeric element 32, 88 and sheet 22using one of a variety of sources including conduction, induction,radiation and/or convection. As in the previous embodiment, the pressureand temperature ranges may vary depending upon the size and geometry ofthe panel, the gasket material used, the temperature of the gasketand/or sheet, and the surface area of the gasket to contact the panel.It is contemplated that the ranges specified above vary somewhatdepending on the specific application. Following the application ofpressure and optional heat (approximately between 3 to 30 seconds) theheat and pressure are removed and the finished assembly is removed andforwarded as finished goods (FIG. 5K).

In addition to the steps outlined above, or if it is found to beimpractical to apply heat to the contact surface between the premoldedpolymeric material and sheet 22 while in tool 50a, or it is found to beundesirable the heat and/or pressure may be applied in a separatefixture. In an alternative to the steps outlined above, or in additionthereto, the steps illustrated by FIGS. 6A-6E may be followed. It shallbe assumed, for the purposes of this discussion, that some or all of theabove steps have been completed to initially bond gasket 32 and/or trimpiece 88 to sheet 22 to form panel assembly 20. Panel assembly 20 may bemoved to a separate fixture, such as 100, having a profiled recessadapted to receive and seat gasket 32, such that surface 36 has apositive relief with respect to surface 102 (FIG. 6A). Sheet 22 mayagain be forced into intimate contact against surface 36 (FIG. 6B).Substantially simultaneously with the application of pressure, energymay also be directed onto or through sheet 22 to heat frit layer 30 orcontact boundary 90 between gasket 32 (or trim piece 88) and sheet 22.The source of the energy may again constitute or include the varioussources described below with respect to FIGS. 11 and 12. The applicationof pressure and heat is maintained for the desired number of seconds toassure a complete and secure bond of gasket surface such as 36 withsheet 22 (FIG. 6C). Following this step, panel assembly 20 is removedfrom fixture 100 and is prepared for packaging (FIGS. 6D and 6E).

Although the application of heat has been described with respect to theuse of infrared or electromagnetic energy sources, heat may also beapplied by several other sources including conduction, convection,induction and radiation sources. Similarly, the pressure or forcenecessary to urge panel 22 against gasket 32 may be achieved in anautoclave or by the weight of the individual panel on the gasket.

In operation, assuming a substantially flat, rectangular panel 4 feetwide by 2 1/4 feet high and 4 millimeters thick, the perimeter of onesurface of the sheet may be cleaned, as described above, to remove anydebris or other material which may inhibit bonding. A coating of theprimer A-1100-B and promoter A-1167-B mixture made by B. F. Goodrich Co.of Akron, Ohio, is applied in a substantially even coat to the outer 4inches of the perimeter. The primer may be applied directly to a ceramicfrit coating such as 30 shown in FIG. 2, using the frit coating as agauge for the distribution of the primer. Once the primer is applied,the frit layer and/or sheet is preheated using one of the energy sourcesdescribed below. It is preferred that the energy generated by the sourcebe absorbed by and heat the ceramic frit layer, drying the primer bydriving off any remaining solvents therein, as well as heat the surfaceof the panel adapted to receive the gasket.

substantially simultaneously with the preparation and preheating of thepanel, one or more gaskets of pre-determined shape and profile areformed in the molding tool, as described above. The preferred method offorming the gasket is injection molding using PVC. A preferred PVC isthat made by Vista Chemical Co. described above. The heated PVC materialis injected into a mold cavity formed by the mold halves pressed tightlytogether. The hot PVC, together with the pressure used to inject the PVCinto the mold, increases the temperature level of the PVC to about 385°F. The gasket is allowed to harden or cure to the shape defined by themold. Less than one minute later, the mold is opened and the heatedsheet is located on the newly formed gasket which has cooled to atemperature of approximately 125° F. A pressure of approximately 7 to 70psi is applied to the panel and gasket to press the two together. Theapplication of the pressure, together with the residual heat retained byboth the gasket and the panel, activates the primer on the bondingsurface. The heat activated primer interacts with the PVC material ofthe gasket, bonding the gasket to the sheet or frit layer. Additionalheat is introduced to the frit layer preferably by directing energythrough the sheet on a side opposite to that of the gasket using acontrolled, focused infrared energy source described below. The addedheat further increases the activation level of the primer with thegasket and improves adhesion. Although both heat and pressure do notneed to be applied simultaneously, it is preferred that both be appliedfor between 3 and 30 seconds. After that time, the heat and pressure arewithdrawn and the contact between the panel and the gasket is allowed tocool for approximately 10 to 15 seconds. After cooling, the glass paneland bonded gasket forming the panel assembly, are moved on in theassembly process as finished goods.

For example, a one-eighth inch thick sheet of glass nine inches squareincluding a frit layer on one surface had a PVC gasket bonded theretosimilar in cross section to that shown in FIG. 2 and having a one inchwide bonding surface. The gasket was molded using injection moldingtechniques in a 250 ton press using 200 tons of clamping pressure. ThePVC melt temperature was 380° F. and had a nine second cure time in themold. While the gasket was being formed, the glass sheet was locallyheated to 300° F. After the gasket was formed, the mold was opened andthe 300° F. panel was located with respect to the gasket which hadcooled to approximately 125° F. A force of 14 psi was applied forapproximately 7 seconds, forcing the panel and gasket against eachother. Simultaneously with the application of the force, the frit layerwas heated using a focused infrared source described below.

FIGS. 7-10 illustrate different embodiments of gasket or grommetsmanufactured by any one of the methods outlined above and specificallyadapted for use in flush-mounted panel assemblies. In FIG. 7, assembly220 includes a sheet-like panel 222 having opposite surfaces 224, 226terminating in a peripheral edge 228. Surface 226 includes a ceramicfrit coating 230 which is bonded to a profiled gasket 232 by a primercoating 248. Profiled gasket 232, in this embodiment, is made from amodified PVC blend or other material having favorable compression setproperties, and includes an arciform, curved body 234 of generallyuniform thickness terminating laterally in securing surfaces 236, 238which are bonded by primer 248. One example of gasket material is a TPRsuch as Shell Kraton G-7430 produced by Shell Chemical Co. of Houston,Tex. Although body 234 and surfaces 236, 238 may have the samethickness, it is contemplated that body 234 may have a wall thicknesswhich is gradational or different from that of surfaces 236, 238.Moreover, the thickness or width of each surface 236, 238 may bedifferent from each other as will become readily apparent below. Bondingsurfaces 236, 238, surface 226 (frit 230) of sheet 222, and the innerwall 240 of arciform body 234 form a gas-filled chamber or bulb 239.Chamber 239 may be in fluid communication with the exterior through oneor more perforations (not shown) extending through body 234 to allow thebody to be compressed and form a tight seal. Instead of a gas-filledchamber providing the sealing force, it is found that the memory of thegasket, and cross-sectional profile are often sufficient to accomplishthe seal.

In FIG. 8, a flush-mounted panel assembly 320 includes a sheet-likepanel 322 having substantially parallel surfaces 324, 326 terminating ina peripheral edge 328. Bonded to frit layer 330 on surface 326, usingany one of the above-described techniques, is an arciform gasket 332having a bulbous body 334 terminating at its base in securing flanges342 and 344. Flanges 342, 344 are preferably, but not necessarilyparallel to surface 326, co-planar with each other, and extend inopposite directions in order to bond with surface 326. Just as in theprevious embodiment shown in FIG. 7, flanges 342, 344 and body 334 mayhave constant or gradational thicknesses depending upon the desiredfunction. For example, arciform body wall 340 defining chamber 339 maybe thinner than one or both flanges 342, 344.

In FIG. 9, flush-mounted panel assembly 420 includes a sheet-like panel422 having opposing surfaces 424 and 426 and a peripheral edge 428. Fritlayer 430 on sheet or panel 422 is bonded, using any one of the abovemethods, to gasket 432 adapted to space sheet 422 from pinch flange 402,as well as seal gap 404 between sheet metal 406 and peripheral edge 428.Gasket 432 includes an arciform body 434 terminating in securing flange442 at one end and a second securing flange 444 at an opposite end.Securing flange 444 extends laterally away from arciform body 434 andbeyond peripheral edge 428 of sheet 422 to form a lip 446. When assembly420 is disposed within the opening defined by pinch flange 402 such thatarciform body 434 engages pinch flange 402, and when assembly 420 isproperly centered therein, lip 446 at the end of securing flange 444drags across sheet metal 406 and barricades gap 404, forming a sealtherein. With panel assembly 420 properly located within the vehicleopening defined by pinch flange 402, outer surface 424 of panel 422 issubstantially flush with the surface defined by sheet metal 406. Panelassembly 420 provides a more aerodynamic fit and style producing lesswind noise than conventional mounting techniques. A further advantageassociated with this assembly, as well as those described below, is therelative ease of assembly.

FIG. 10 illustrates an embodiment 520 of the panel assembly whereinsurface 526 and/or frit layer 530 is bonded to an arciform gasket 532.Gasket 532 has an arciform body 534 terminating in securing flanges 542,544 to define a gas-filled chamber 539. Securing flange 542 has anextended thickened portion 546 inboard of body 534 in which a stud 508has a head 509 captured during molding. Shank 510 of stud 508 is adaptedto be received or extend through a hole 512 formed in pinch flange 502.Arciform or bulbous body 534 acts both as a spacer and as a cushion forpanel 522 when assembly 520 is disposed within the opening. Assembly 520may also be aided in its positioning within the opening defined by pinchflange 502 by locating shaft 510 in hole 512. A threaded nut or pressurecap may retain stud 508 in hole 512 from an opposite side of pinchflange 502. Assembly 520, like the other embodiments, may also beretained within the opening by a suitable adhesive disposed between thesheet and/or gasket and pinch flange. The type of adhesive may varydepending upon the particular needs of the automobile assembler. Onecommon type of adhesive is known as BETASEAL, produced by Essex ChemicalCorporation of Sayerville, N.J. The BETASEAL brand adhesive is designedto provide a secure bond between a glass panel and a sheet metal surfacetypically encountered in vehicle window assemblies.

Panel assembly 620 (FIG. 11), for use on Class "A" surfaces such asvehicle windshields, includes a sheet-like panel 622 of glass which maybe laminated, tempered or otherwise strengthened and has a predeterminedsize and geometry. An outer surface 624 is bonded to a spacer/gap seal626 using any one of the methods described above. Combination spacer/gapseal 626 has a generally arcuate upper profile 628 which extends awayfrom sheet 622 and is generally parallel to surface 624. The extensionof seal 626 forms a resilient, flexible lip 630 which engages sheetmetal 632 to seal the gap between the peripheral edge 634 of sheet 622and sheet metal 632. Extending perpendicularly from the lower surface ofseal 626 is a generally rigid flange 636 adapted to space sheet 622 apredetermined distance from pinch flange 638. Assembly 620 is retainedwithin the opening defined by pinch flange 638 by a bead of BETASEAL orother suitable adhesive 640 bonding panel 622 to pinch flange 638.

Although each of the above embodiments of the gasket bonded to the sheetor panel have been described generally as made from a polymericmaterial, it is preferred that PVC be used. Because PVC offers severaladvantages over other materials including ease in handling, it isreadily available, inexpensive and recyclable. Moreover, PVC material issubstantially resistant to ultraviolet radiation and is substantiallyflexible and resilient in a variety of climatic conditions. Although PVCis preferred, a modified PVC blend or other material having favorablecompression set properties may also be used including RIM urethane andthermoplastic elastomers.

The above method of forming the gaskets and bonding them to thesheet-like panels offers several distinct advantages including changingcross sections and unusual or complex profiles for a particular paneldepending upon specific design aspects such as disclosed in FIG. 1.Moreover, based upon the potential range of applications of the abovepanel assemblies, the Durometer hardness of the material may vary. Forexample, a Durometer hardness within the range of 55 to 90 will besufficient for many applications. But where it is desired for oneportion of the gasket to be flexible while another portion is stiff, alow Durometer material may be used with a material build-up used tocreate the stiff or harder portion of the gasket.

FIGS. 12 and 13 are schematic representations of two energy sourcesmentioned above that may be used to heat the frit layer and/or contactboundary between a panel such as 22 and a gasket such as 32 describedabove in relation to FIG. 2. Although each source is described inrelation to producing a characteristic energy spectrum, such is by wayof example only. Other energy sources may be equally effective inheating the frit layer/contact boundary such as convective, conductive,inductive and resistive heat sources. Moreover, microwave energy may beused as well.

FIG. 12 generally illustrates a controlled, focused infrared (CFIR)source 700 which may be used in both the preheating of the sheet priorto receiving the gasket, as well as heating with or without theapplication of pressure after the sheet and gasket contact each other.

CFIR 700 includes one or more infrared emitter assemblies 702 such asModel 5305-104 made by Radiant Energy Research, Inc. of Minneapolis,Minn., and disposed above sheet 722 in a pattern conforming to thatregion of sheet 722 adapted to receive gasket 732. In the alternative, asingle infrared emitter assembly may be moved above sheet 722 by aguided robotic arm in a pattern conforming to that area to receivegasket 732. Computer/process controller 704 preferably causes infraredemitter assembly 702 to emit infrared energy into sheet 722 from a sideopposite that containing frit coating 730 and primer coating 748although it may also be directed from the same side as the frit layer730 and primer 748. A spectrophotometer 706 coupled to computer/processcontroller 704, detects the energy reflected and radiated from sheet722. Based upon the feedback from spectrophotometer 706, controller 704adjusts the power of infrared energy emitted by assembly 702 to obtainmaximum absorption by frit layer 730 and primer 748 and raise thetemperature level to between 100° F. and 350° F. Although CFIR 700 hasbeen described for use in both heating steps, it is contemplated that itwill be most effective to heat the frit layer/contact boundary after thegasket is located with respect to the sheet.

FIG. 13, schematically illustrating a controlled area infrared (CAIR)source 800, may include one or more infrared emitters 802 such as ModelFB122425B3 made by Casso-Solar Corp., of Pomona, N.Y., and may bedistributed above and aligned with sheet 822. Radiation generated byemitter 802 is controlled by a controller 804 based upon input from athermocouple 806 attached to emitter 802, and a spectrophotometer 808angularly disposed with respect to sheet 822. A reflector 810 may bedisposed beneath sheet 822 to reflect heat energy back into the sheet.Sheet 822 may be supported above reflector 810 by insulator blocks orspacers 816 to prevent heat loss by conduction into reflector 810.Contemplated in both of the heating options, but shown only in FIG. 13,is a plenum 812 and exhaust fan 814, to vent fumes driven off during theheating process. Moreover, each sheet may be properly located withrespect to each heating source by using a template or guide for eitherthe panel or sheet such as 818 or gasket (708 in FIG. 12).

Since the radiation produced by emitter 702 preferably is introducedinto sheet 722 from a side opposite that containing primer coating 748,it is preferred that sheet 722 have a high transmissivity to thewavelength of radiation selected. Emitters 702 and 802 both are capableof producing infrared radiation having a wavelength greater than 7.0×10³Angstroms (A). The transmissivity of the radiation through each sheet isgreatly affected by its particular characteristics. For example, tintedor opaque panels may have a lower transmissivity since the pigments orcoloration within the material may absorb a portion of the radiation.For materials having lower transmissivities, it is preferred to selectwave lengths of radiation which promulgate better through the materials,yet are absorbed by the frit layer at the contact boundary between thesheet and primer coating. In the preferred embodiment of this invention,sheets 22 are glass sheets and may be single sheets or laminated sheets,depending on the desired function in the vehicle.

In order to reduce problems associated with heating and cooling largeexpanses of glass or plastic panels, it is preferred that each of theabove radiation sources direct their energy to an areally restrictedportion of the panel or sheet. For example, since it is desired to heatonly that portion of the sheet adapted to engage the gasket, each energysource 702, 802 may be adapted so that the radiation is applied only tothe peripheral margin or other location receiving the gasket.Alternatively, each source may be moved around the sheet by a guidedrobotic arm, as mentioned above or a mask may be used to limit theexposed area. Moreover, one or more emitters such as 702, 802 may berecessed within a tool patterned to coincide with the area of the panelto be heated.

FIGS. 14-15 illustrate two techniques for forcing each sheet intocontact with each gasket. Preferably, one method and apparatus (FIG. 14)includes the creation of a negative pressure or vacuum within chamber900 formed by the inside perimeter of gasket 932 within tool half orfixture 902, surface 926 of sheet 922 and surface 904 of tool 902.Suction lines 906 extending through tool 902 are coupled to a vacuumsource (not shown). The vacuum created in chamber 90 causes sheet 922 tobe forced downwardly by atmospheric pressure against bonding surface 936of gasket 932.

An alternate method and apparatus (FIG. 15) of forcing sheet 922 intocontact with gasket 932 is by the mechanical application of pressure orforce on sheet surface 924 substantially opposite surface 926 receivinggasket 932. It is contemplated that a variety of mechanisms may be usedto exert the force, pushing the sheet and gasket together, includingrams, either hydraulic or pneumatic, associated with the opposite toolhalf, a panel carrier, robotic arm and the like. In one method, thesheet and gasket are forced against each other in the molding tool suchas 50, 50A described above by the tool half not retaining the gasket.Pressure feet or pads may be located between surface 924 and theopposite tool half such as 62 in order to precisely locate the force onsurface 924.

As briefly outlined above, a variety of mechanisms exist for placingsheet 22 into intimate contact with the bonding surface of gasket 30. Itis contemplated by this invention that the location of gasket 30 andsheet 22 may be reversed to obtain substantially the same results.

Although the invention has been described with respect to specificpreferred embodiments thereof, many variations and modifications willbecome apparent to those skilled in the art. It is, therefore, theintention that the appended claims be interpreted as broadly as possiblein view of the prior art to include all such variations andmodifications.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A panel assemblycomprising:a panel having first and second surfaces and a peripheraledge; a gasket formed separately from said panel and having an arciformbody; and a heat-activated primer composition between said panel andsaid gasket for bonding said arciform gasket to a single surface of saidpanel.
 2. A panel assembly as recited in claim 1, further including afrit layer deposited between said gasket and said panel.
 3. A panelassembly as recited in claim 2, further comprising first and secondsecuring flanges spaced apart from each other and extending from saidgasket and having portions adapted to engage said panel.
 4. A panelassembly as recited in claim 3, wherein said arciform body and first andsecond securing flanges cooperate with said panel to form a chamber. 5.A panel assembly as recited in claim 4, wherein said first securingflange defines a lip seal extending outwardly from said gasket andbeyond said peripheral edge.
 6. A panel assembly as recited in claim 5,further comprisinga fastener molded within and captured by said secondsecuring flange for mechanically fastening said panel assembly in anopening.
 7. A panel assembly as recited in claim 4, further comprising alip seal formed separately from said panel and extending from saidgasket beyond said peripheral edge of said panel and adapted to engage asurface of said panel adjacent said gasket.
 8. A panel assembly asrecited in claim 1, wherein said panel is glass;said gasket formed froma polymeric material and bonded to said first surface of said panel; afrit layer attached to said first surface; and said primer compositioncoating at least a portion said frit layer.
 9. A panel assembly,comprising:a panel having first and second surfaces terminating in aperipheral edge; a gasket formed separately from said panel and havingan arciform body and first and second securing flanges spaced apart fromeach other and adapted to engage said panel; a heat-activated primer forattaching said first and second securing flanges to said panel; andwherein said arciform body, panel, and first and second securing flangescooperate to form a chamber.
 10. A panel assembly as recited in claim 9,wherein said gasket is preformed from a polymeric material.
 11. A panelassembly for use in a vehicle opening comprising:panel of size andgeometry adapted to fit in the vehicle opening, said panel having firstand second surfaces, each terminating in a common peripheral edge; afirst polymeric gasket formed separate from said panel and adapted toengage at least a portion of said panel along said first surfaceproximate said peripheral edge; a second polymeric gasket formedseparate from said panel and adapted to engage at least a portion ofsaid panel along said second surface; and a primer for bonding saidfirst and second gaskets to said first and second surfaces of saidpanel.
 12. A panel assembly as recited in claim 11, wherein said firstgasket includes:a first and second securing flanges each having abonding surface secured to said panel; and an arciform bodyinterconnecting said first and second securing flange, said arciformbody having an inner wall, together with said panel, defining a gasfilled chamber.
 13. A panel assembly as recited in claim 12, whereinsaid first securing flange defines a lip seal extending beyond theperipheral edge of said panel for engaging the vehicle.
 14. A panelassembly as recited in claim 13, wherein said first gasket is formedabout and captures a fastener for locating said panel in the vehicleopening.
 15. A panel assembly as recited in claim 11, wherein saidsecond gasket includes a seal having a flexible, resilient lipprojecting beyond the peripheral edge of said panel from said secondpanel surface.
 16. A panel assembly as recited in claim 11, including afrit layer on at least one of said first and second panel surfacesbetween said panel and at least on of said gaskets.
 17. A panelassembly, comprising:a panel having a first and second surfacesterminating in a peripheral edge; a frit layer on said first surface ofsaid panel proximate said peripheral edge; a gasket having an arciformbody and first and second securing flanges spaced apart from each otherand adapted to engage said panel to form a chamber; and aheat-activatable adhesion promoting primer on at least one of said paneland said gasket for bonding said gasket to said panel.